Mandatory energy audit on sale: what it gives the buyer in price negotiation

The buyer of a residential building rated D to G now has, before even making an offer, a document that the seller is required to hand over at the first viewing: the energy audit. This document is not just one more diagnostic in the technical diagnostic file. It sets out, in orders of magnitude, a staged programme of works, and in doing so reveals part of the energy capex that the buyer will have to bear to keep the asset usable. What remains to be seen is what the audit actually allows in price negotiation, what it does not allow, and what remedies exist where it is missing, incomplete or understated. This guide treats the mandatory energy audit on sale as an instrument for arbitrage on the value of the asset, and not as a notarial formality.

The exact scope of the mandatory energy audit: a narrower obligation than is assumed

The first misreading, common on the buyer's side as on the seller's, is to think that every sale of an energy-inefficient property triggers an energy audit. The text is more restrictive.

Article L. 126-28-1 of the French Construction and Housing Code covers buildings or parts of buildings for residential use that comprise a single dwelling or several dwellings not subject to Law No. 65-557 of 10 July 1965 and that fall within classes D, E, F or G within the meaning of Article L. 173-1-1. In other words: a detached house, an investment building held in single ownership, a building not subject to the co-ownership (copropriété) regime. A co-ownership unit, even one rated G, does not fall within the scope of the audit obligation. For such a unit, the buyer will have to build its reasoning on the energy performance certificate (DPE) and, where one exists, on the global technical diagnosis (DTG) under Article L. 731-1.

This distinction has a direct consequence for acquisition strategy. On an investment building in single ownership, the buyer receives a costed programme of works for the whole building. On a co-ownership unit, the buyer has only an energy rating for the unit, with no structured view of the works to be undertaken on the common parts, unless the DTG and the minutes of general meetings are obtained.

The timetable for entry into force, class by class

Paragraph VII of Article 158 of Law No. 2021-1104 of 22 August 2021 on combating climate change and strengthening resilience to its effects phases in the obligation. It sets the date at 1 January 2022 for dwellings in classes F and G, 1 January 2025 for class E, and 1 January 2034 for class D.

Paragraph VIII of the same article provides a separate timetable for Guadeloupe, Martinique, French Guiana, La Réunion and Mayotte: classes F and G from 1 July 2024, class E from 1 January 2028.

At the date of writing, the audit is therefore required in mainland France for sales of single-ownership properties rated E, F or G. To write that the audit concerns only energy-inefficient properties, that is, classes F and G, has been inaccurate since 1 January 2025. A buyer negotiating a house rated E to whom no audit is presented should draw a first conclusion about how well the sale file has been prepared.

The exclusion of sales of buildings to be constructed

Article L. 271-4 specifies that the documents mentioned in point 6° of paragraph I, that is, the DPE and, where applicable, the energy audit, are not required in the case of a sale of a building to be constructed as referred to in Article L. 261-1. A buyer in an off-plan sale (VEFA) therefore has no audit to expect: the buyer's contractual lever lies elsewhere, in the descriptive notice and the performance promised by contract.

The content of the audit: a staged programme of works, orders of magnitude, not a quotation

Article L. 126-28-1 imposes a precise content, which must be read word for word before it is made an argument in price negotiation.

The energy audit sets out in particular proposals for works. These proposals must be compatible with the easements provided for by the Heritage Code and involve a cost that is not disproportionate to the value of the property. These proposals set out a coherent programme of works in stages to achieve a high-performance energy renovation.

Three elements structure this programme. The first stage enables at least class E to be reached. The programme also provides for the works needed to reach class B where technical, architectural or heritage constraints or the cost of the works do not prevent that level of performance from being reached. Finally, the audit states for information only the theoretical impact of the works on the energy bill, provides orders of magnitude of the associated costs and lists the public subsidies available.

The wording chosen by the legislature calls for caution on the buyer's part. An order of magnitude is not a contractor's quotation, and a theoretical impact on the bill is not an observed saving. These figures were drawn up without consulting contractors, without a structural study, without an asbestos survey prior to works, and without including the site-specific extra costs of Parisian buildings (access, scaffolding on the public highway, constraints imposed by the Architecte des Bâtiments de France where the property is in a protected area). A buyer who took the audit figure as it stands to calculate its discount would risk underestimating the real energy capex.

The audit nonetheless retains considerable negotiating value, for a reason that follows from its purpose: it sets out in writing, before the offer, that the asset does not reach the level of performance that will ultimately be required and that a programme of works is necessary. It moves the debate from the subjective register of market assessment to that of a documented regulatory constraint.

The independence of the auditor

The same article requires that the professional responsible for preparing the energy audit must have no connection that could undermine his or her impartiality and independence with respect to the owner or the agent who engages him or her. Article L. 271-6 reinforces this requirement for all the documents in the technical diagnostic file: guarantees of competence, appropriate organisation and resources, insurance covering the consequences of a finding of liability, and no connection undermining impartiality with either the owner or a business that may carry out works on the structures concerned.

Since Law No. 2025-594 of 30 June 2025, Article L. 271-6 also provides that a publicly available directory lists the persons in practice mentioned in the first paragraph. For an institutional buyer, checking the registration of the author of the audit and the author's insurance has become a zero-cost due diligence point, to be documented before signing.

Delivery at the first viewing: a decisive point of timing

Article L. 271-4 sets out two distinct timings, often confused in practice.

The technical diagnostic file as a whole is annexed to the preliminary sale agreement (promesse de vente) or, where there is no such agreement, to the notarised deed of sale (acte authentique). In a public sale, it is annexed to the specification of terms of sale.

The energy audit follows a rule of its own: The energy audit mentioned in point 6° of this paragraph I is handed over by the seller or the seller's representative to the potential buyer at the first viewing of the building or of the part of the building that is the subject of such an audit. It may be handed over by any means, including electronically.

This priority in time is the buyer's real lever. The information on energy capex is owed to the buyer before an offer is made, and not at the stage of notarial completion. An informed buyer draws two operational reflexes from this: time-stamping the handover, or its absence, by a summary email sent to the agency after the viewing; and making the offer conditional on the actual communication of the complete audit, annexes included.

The absence of delivery at the first viewing does not in itself give rise to a quantified right to a price reduction, as will be seen below. But it is a factual element that can be used on the ground of the pre-contractual duty to provide information, and it weakens the position of a seller who later argued that the buyer knew the energy condition of the property.

From audit to energy capex: the buyer's method of restatement

Turning an audit into an argument in price negotiation requires restatement work in four stages.

• Separate the regulatory stage from the optimisation stage: the first stage of the programme, the one that reaches class E at a minimum, corresponds to the regulatory threshold with a known horizon. The following stages, up to class B, are a matter of value arbitrage, not constraint.
• Have the first stage re-costed by two contractors or a project manager (maître d'œuvre), during the term of the preliminary agreement, to replace the audit's orders of magnitude with an execution cost.
• Include the peripheral costs that the audit does not include: asbestos survey before works, possible asbestos removal, replacement of services, rental vacancy during the works, project management fees, price indexation.
• Position this capex in the financing plan and the yield calculation, and not in a mere request for a lump-sum discount.

The difference between a buyer who asks for a price reduction and a buyer who puts forward a documented capex is procedural as much as economic. The first negotiates on value, ground on which the law offers no support. The second negotiates on objectified technical information, ground on which legal arguments are available.

This distinction is written into the texts. Article 1137 of the French Civil Code states that it is not fraud (dol) for a party not to disclose to the other party its estimate of the value of the performance. Article 1112-1 specifies for its part that the duty to provide information does not extend to the estimate of the value of the performance. The seller therefore never has to share its assessment of the value of the property. The seller must, however, deliver the energy information itself. The buyer's argument must target that information, not the price.

The usability of the asset over time: the real subject of the negotiation

For an investor, the question is not thermal comfort but the ability to let the asset, at what rent and for how long. Three sets of provisions govern this usability, and the audit is the reading grid for them.

Energy decency

Article 6 of Law No. 89-462 of 6 July 1989, in the wording in force since 1 January 2025, requires the landlord to deliver a dwelling meeting a minimum level of performance within the meaning of Article L. 173-1-1 of the Construction and Housing Code. The performance level of a decent dwelling is:

• from 1 January 2025, between class A and class F;
• from 1 January 2028, between class A and class E;
• from 1 January 2034, between class A and class D.

In the overseas territories, the timetable is shifted: between classes A and F from 1 January 2028, between classes A and E from 1 January 2031. The text specifies that dwellings that do not meet the aforementioned criteria by the dates set are considered not to be decent.

An asset rated E acquired today therefore falls outside the scope of lettings as a main residence on 1 January 2028, unless works are carried out. For a buyer reasoning in terms of ten-year yield, this date is not a diffuse risk: it is a date on which the rental income stream breaks, to be built into the business plan in the same way as a refinancing date.

The cap on re-letting rent

Article 17 II of the Law of 6 July 1989 adds an immediate yield constraint: where a dwelling in class F or class G, within the meaning of Article L. 173-1-1 of the Construction and Housing Code, is let anew, the rent under the new lease may not exceed the last rent charged to the previous tenant. These provisions apply to leases entered into, renewed or tacitly renewed since 24 August 2022, and in the overseas territories after 1 July 2024.

The buyer of a let energy-inefficient property therefore cannot count on a rental catch-up on re-letting to fund the works. The capex precedes the income. This is a price negotiation argument that is all the stronger for being quantifiable: the difference between the capped rent and the market rent, multiplied by the probable period before the works are completed.

The performance obligation under Article L. 173-2

Distinct from decency, the obligation in Article L. 173-2 of the Construction and Housing Code provides that from 1 January 2028, the performance level of buildings or parts of buildings for residential use is between classes A and E. Two exemptions are provided for: buildings that, by reason of their technical, architectural or heritage constraints, cannot undergo works to reach that level, and those for which the cost of the works enabling the obligation to be met is manifestly disproportionate to the value of the property. The criteria for these exemptions are left to a decree of the Conseil d'État.

Paragraph II of the article postpones the obligation to 1 January 2033 for five categories of co-ownerships in difficulty: safeguard plan, OPAH perimeter with a recovery component, operation to requalify degraded co-ownerships, appointment of a provisional administrator, state of default (état de carence). For a buyer in distressed real estate, this list is to be checked before any arbitrage: it changes the horizon of the constrained capex.

Finally, paragraph III requires, since 1 January 2022, where the property does not comply with paragraph I, that the obligation be mentioned in advertisements relating to the sale or letting and in deeds of sale or leases. The absence of this mention in the deed is a point of control to be raised against the drafter.

Mentions in advertisements and their sanction

Article L. 126-33 requires advertisements for sale or letting, including on digital platforms, to state the rating of the property in terms of energy performance and greenhouse gas emissions, together with an indication of the amount of theoretical expenditure. A professional in breach is liable to an administrative fine of up to €3,000 for an individual and €15,000 for a legal entity; a non-professional, to a fine of €3,000 after formal notice (mise en demeure). The interest for the buyer lies not in the fine, which does not benefit the buyer, but in keeping a capture of the advertisement: it fixes the information provided upstream and may contradict the seller's later position.

Audit missing, erroneous or understated: what the buyer can actually obtain

This is where a naive reading of the texts most often leads to a strategic error.

The specific civil sanctions of the technical diagnostic file do not cover the audit

Paragraph II of Article L. 271-4 sets out two distinct sanctions, exhaustively listed. Where, at the signing of the notarised deed, one of the documents mentioned in points 1°, 2°, 3°, 4°, 7° and 8° of paragraph I is missing or out of date, the seller cannot be released from the corresponding warranty against latent defects (vices cachés). Where the documents mentioned in points 5° and 12° are missing, the buyer may seek termination of the contract or ask the court for a reduction of the price.

The DPE and the energy audit fall under point 6°. They appear in neither of these two lists. The absence of an audit therefore does not give rise automatically to a price reduction, nor to the automatic loss of the clause excluding the warranty against latent defects. Any claim must be built on the general law.

The last paragraph of paragraph II adds a point that should not be over-interpreted: the buyer may not rely against the owner on the recommendations accompanying the energy performance certificate or on the document relating to noise exposure plan zones, which are of indicative value only. It is the recommendations that are deprived of effect, not the DPE as a whole, still less the energy rating. In relation to lettings, Article L. 126-29 follows the same logic, describing the recommendations as being of informative value only.

The general-law grounds available

Three routes, of different natures, must be assessed file by file.

The pre-contractual duty to provide information under Article 1112-1 of the French Civil Code: a party who knows information of decisive importance for the other party's consent must inform the other party of it, and the parties may neither limit nor exclude this duty. The text specifies the burden of proof: a person who claims that information was owed to him or her must prove that the other party owed it, and the other party must prove that it was provided. The sanction is twofold: liability of the person bound by the duty and, where appropriate, annulment of the contract under the conditions of Articles 1130 et seq.

Fraud (dol) under Article 1137, where the seller intentionally concealed information that the seller knew to be decisive: audit deliberately kept out of the file, substitution of an earlier, more favourable DPE, withholding of a technical report known to the seller. The reservation in the third paragraph remains, since an estimate of value does not fall within the scope of fraud.

The warranty against latent defects under Articles 1641 and 1644, which requires a latent defect making the thing unfit for the use for which it is intended, or so reducing that use that the buyer would have paid a lower price. Article 1644 gives the buyer the choice of returning the thing against reimbursement of the price, or keeping it and having part of the price returned. This is the price reduction action (action estimatoire), the only genuinely quantified mechanism for recovering capex after signing, but its success depends on the existence of a latent technical defect and not on the mere gap in rating.

Recourse against the author of the audit or of the DPE

Where the audit exists but proves to be erroneous, the liability of its author is built on Article L. 271-6: guarantees of competence, appropriate resources, compulsory insurance, independence from the owner and from any business that may carry out the works. To this is added the requirement of impartiality and independence specific to the auditor under Article L. 126-28-1. The compulsory insurance has an obvious practical interest: it secures the solvency of the debtor, which an individual seller does not always offer.

Caution is required, however, on the assessment of loss. There is no scale, and the amount is a matter for the sovereign assessment of the trial courts. To tell a client to expect a recovery equal to the cost of the works is a promise that the positive law does not guarantee.

Translating the analysis into the contractual documentation

The outcome of the price negotiation is decided less in the exchange of offers than in the drafting of the preliminary agreement. A few points of vigilance, on the buyer's side, deserve to be made systematic.

• Annex the audit to the preliminary agreement and have the deed record the date of its actual delivery, so as to lock in compliance with the obligation to deliver at the first viewing.
• Provide for a condition precedent of obtaining contractors' quotations for the first stage of the programme of works, with a cost ceiling beyond which the buyer withdraws or renegotiates.
• Obtain a statement from the seller that no works affecting energy performance have been carried out since the DPE and the audit were prepared, and that the seller has no other technical report in its possession.
• On an investment building, obtain the rent roll with the rating of each dwelling, in order to identify the units that will fall outside the decency standard on the 2028 and 2034 dates.
• In co-ownership, require the DTG where one exists, which Article L. 731-1 specifies shows a summary assessment of the cost and a list of the necessary works, specifying in particular those that should be carried out in the next ten years, together with the minutes of general meetings and the state of the works fund.
• Check the period of validity of the DPE and the audit against the regulatory texts in force on the date of signing, Article L. 126-26 leaving that period to regulation.

Conclusion

The mandatory energy audit on sale is not a compliance document, it is a valuation document. It gives the buyer no automatic right to a price reduction, since the legislature deliberately kept point 6° of Article L. 271-4 outside the two specific civil sanction regimes of the technical diagnostic file. It gives the buyer something better: written technical information, delivered before the offer, enforceable against the seller on the ground of the duty to provide information, and directly convertible into energy capex in the financing plan.

The position we take is simple. Price negotiation must never turn on value, ground on which Articles 1112-1 and 1137 of the French Civil Code leave the buyer without any support. It must turn on the timeline of the asset's usability: class E excluded from letting on 1 January 2028, class D on 1 January 2034, re-letting rent frozen as of today for classes F and G. These dates are the real object of the arbitrage.

Before any offer on an asset rated D to G, have a contractor re-cost only the first stage of the programme of works, the one that reaches class E at a minimum, and compare that amount with the order of magnitude given in the audit. The gap observed is your documented negotiating margin. The rest of the programme, up to class B, is a matter of your asset strategy, not of regulatory constraint.

Frequently asked questions

Is an energy audit mandatory for the sale of a co-ownership apartment rated G? No. Article L. 126-28-1 of the French Construction and Housing Code covers buildings or parts of buildings for residential use comprising a single dwelling, or several dwellings not subject to the Law of 10 July 1965 establishing the co-ownership regime. A co-ownership unit is therefore outside the scope of the audit obligation, whatever its class. The buyer will have to base its capex analysis on the unit's DPE, on the global technical diagnosis under Article L. 731-1 where one exists, and on the general meeting decisions relating to works.

Does the energy audit concern only energy-inefficient properties rated F and G? No. Paragraph VII of Article 158 of Law No. 2021-1104 of 22 August 2021 phased in the obligation: classes F and G from 1 January 2022, class E from 1 January 2025, class D from 1 January 2034. In mainland France, the sale of a single-ownership property rated E therefore now requires an audit. In the overseas territories, paragraph VIII of the same article sets 1 July 2024 for classes F and G and 1 January 2028 for class E.

When must the seller hand over the energy audit? Article L. 271-4 of the French Construction and Housing Code provides that the audit is handed over by the seller or the seller's representative to the potential buyer at the first viewing of the building, by any means, including electronically. The technical diagnostic file as a whole is, for its part, annexed to the preliminary sale agreement or, where there is none, to the notarised deed. These two timings are distinct and must not be confused.

Does the absence of an energy audit entitle the buyer to a reduction of the sale price? Not as of right. Paragraph II of Article L. 271-4 deprives the seller of the clause excluding the warranty against latent defects only where the documents in points 1°, 2°, 3°, 4°, 7° and 8° are missing, and gives rise to termination of the contract or a price reduction only for the documents in points 5° and 12°. The DPE and the audit fall under point 6° and appear in neither list. The buyer must therefore rely on the general law: the duty to provide information under Article 1112-1 of the French Civil Code, fraud under Article 1137, or the warranty against latent defects under Articles 1641 and 1644.

Do the works amounts shown in the audit bind the seller? No. Article L. 126-28-1 specifies that the audit states for information only the theoretical impact of the works on the energy bill and provides orders of magnitude of the associated costs. It is neither a quotation nor a contractual undertaking. A buyer who intends to quantify a request for a price revision must obtain contractors' quotations during the term of the preliminary agreement, including the peripheral costs that the audit does not include.

From when will a dwelling rated E no longer be lettable? Article 6 of the Law of 6 July 1989, in the wording in force since 1 January 2025, sets the performance level of a decent dwelling between classes A and F since 1 January 2025, between classes A and E from 1 January 2028, and then between classes A and D from 1 January 2034. A dwelling rated E therefore remains lettable until 31 December 2033, but a dwelling rated F has not been since 1 January 2025. In the overseas territories, the A to F threshold applies from 1 January 2028 and the A to E threshold from 1 January 2031.

What recourse is there against a diagnostician who produced an erroneous audit? Article L. 271-6 of the French Construction and Housing Code requires the professional to have guarantees of competence, appropriate organisation and resources, insurance covering the consequences of a finding of liability, and no connection undermining impartiality, including with a business that may carry out the works. Article L. 126-28-1 repeats this independence requirement for the auditor. Since Law No. 2025-594 of 30 June 2025, a public directory lists professionals in practice, which makes it possible to check the position of the author of the report before signing. The assessment of loss is, however, a matter for the trial courts, with no scale.